From b6ec79518ef0c84d1ed0f76b8af9592a75eb29b6 Mon Sep 17 00:00:00 2001 From: Hou Tao Date: Thu, 27 Jan 2022 16:32:40 +0800 Subject: [PATCH] bpf, x86: Remove unnecessary handling of BPF_SUB atomic op According to the LLVM commit (https://reviews.llvm.org/D72184), sync_fetch_and_sub() is implemented as a negation followed by sync_fetch_and_add(), so there will be no BPF_SUB op, thus just remove it. BPF_SUB is also rejected by the verifier anyway. Signed-off-by: Hou Tao Signed-off-by: Daniel Borkmann Acked-by: Brendan Jackman Link: https://lore.kernel.org/bpf/20220127083240.1425481-1-houtao1@huawei.com --- arch/x86/net/bpf_jit_comp.c | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 2b1e266..36f6fc3 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -787,7 +787,6 @@ static int emit_atomic(u8 **pprog, u8 atomic_op, /* emit opcode */ switch (atomic_op) { case BPF_ADD: - case BPF_SUB: case BPF_AND: case BPF_OR: case BPF_XOR: -- 2.7.4